SPF Macro Validation – January 08, 2026 (read more)

I came across a "new" feature in SPF records today called macros.  It is an interesting idea that hasn't gained widespread adoption, but something I need to think about if it is useful for any of my customers.  It is one way around the 10 lookup limit that is easy to hit if you use a bunch of 3rd party mailing services, each which require their own SPF record (and sometimes have quite extensive include statements within each record).

One problem with them is that the typical SPF checkers (even those that accept an IP address as well) don't actually lookup the macro, but are basically just testing for syntax, and ignore the macros entirely, so testing the macro can be more difficult.

I have a customer that complained they have an email from a particular vendor that ends up in their spam folder due to a misconfiguration on the sender's end.  We added a whitewlecomelist (I hadn't ever thought about it, but kind of crazy that white and black lists existed for so long...) rule for this sender, so SpamAssassin won't filter out this sender any more, and I wrote up a technical email for them to forward to the vendor, and I thought I should include it here, since some of the information about SPF macro records isn't great.